Magnetic chain feed and separator



p 7, 1937- w. l. SALLEE MAGNETIC Filed June 23, 1954 CHAIN FEED AND SEPARATOR 2 Sheets-Sheet 1 JNvEnTosz h/sssrzz 1T SHLLEE Sept. 7, 1937. w. l. SALLEE 2,092,025

MAGNETIC CHAIN FEED AND SEPARATOR Filed June 25, 1954 2 Sheets-Sheet 2 79 5 19 z? 70 14 JNvEm'orz Y Messrs/e 1'. SAL/.55

Patented Sept. 7, 1937 UNITED STATES- when PATENT orrics MAGNETIC CHAIN AND SEPARATOR Webster I. Sallee, Cleveland, Ohio Application June .23, 1934, Serial No. 732,126

7 Claims.

' This invention relates to a magnetic chain feed The principal object of'the present invention is i to provide a magnetic chain for this purpose in which the magnetic flux is utilized more efficient- 1y than heretofore.

A correlative object is to provide a chain conveyer having concurrently magnetizable prongs extending across the path of travel of the conveyer, adjacent prongs being of opposite polarity when magnetizable concurrently.

Another object is to provide a chain feed mechanism particularly useful in connection with air swept attrition pulverizing mills, and having means for maintaining predetermined desired relationships between the rate of feed of materials by the chain and volume of air admitted to the. grinding mill.

A more specific object is to provide a magnetic chain feed and separator for use in connection with multiple fuel burning systems employing.

both pulverized fuels and fuel oils with means for driving the pump for the oil and the chain in such relation that the same intensity of combustion can be maintained by either, whereby a changeover from pulverized fuel to fuel oil and vice versa may be effected without interruption and merely by a simple clutching and declutching arrangement.

Other objects and advantages will become apparent from the following specification wherein reference is made to the drawings in which plane indicated by the line 44 of Fig. 3;

Fig. 5 is an enlarged fragmentary plan view of the magnetic chain mechanism; and

Fig. 6 is an enlarged fragmentary plan view showing a modified form of the chain.

Referring to- Figs. 1 and 2, the magnetic chain feed and separator mechanism is shown for purposes of illustration as used in connection with an air swept attrition pulverizing mill A, on the frame of which mill the apparatus is mounted. In its preferred form, the feed and separator mech anism comprises a pair of endless chains i and 2 respectively which are mounted to travel along parallel paths in fixed relation to each other. Each of the chains l and 2 carries a plurality of prongs 3 which extend transversely of the pathzof travel of the chains toward the opposite chain a,

and, for purposeslater to be described, are of .a material which is highly conductive of magnetic flux and preferably also such as to become de magnetized readily when out of the influence of any magnetic field. The chains are mounted for continuous movement on suitable sprockets, one pair of the sprockets, indicated at t, being driven for driving the chains along their respective paths of travel while maintaining them in fixed position with respect to each other.

Along the feeding and separating portion of the path of travel the chains are preferably arranged horizontally so that the-material deposited thereon must drop between the prongs 3.

In the form illustrated, loose material to be separated is also to be fed to the mill A for grinding. This material is deposited a suitable feed hopper 6, disposed above the path of travel of theprongs of the chain, the hopper 6 being open at the bottom, as indicated at i, so that the materials 'to be separated may pass therefrom on to and between the travelling prongs 3. Be neath this portion of the path of travel of the prongs 3 is a non-magnetic dead plate 8 over which the prongs of the chain pass. The prongs arearranged to slide on or pass slightly above the plate so that materials discharging from the hopper can drop in between the prongs and be progressed thereby. g

Further along in the direction of travel of the prongs is a non-magnetic receiving hopper H] which communicates with a suitable duct l2 discharging into the grinding mill A, the receiving hopper I0 being disposed beneath the path of travelof the prongs. The. adjustable dead plate 8 to maintain the desired depth of the layer of materials deposited between the prongs extends from beneath the opening I of the hopper 6 at least tothe nearer limit of the non-magnetic hop-per l0 so that any material deposited between the prongs cannot pass entirely therethrough until over the receiving hopper I0. The end wall l3 of the hopper 6 is spaced a sufficient distance above the chains to maintain an even flow of the materials deposited between the prongs.

Referring to Fig. 4, it will be noted that the dead plate 8 is slidably supported in channels 8a which may be on the underside of the tracks i9 hereinafter described. Thus the plate 8 may be slid toward and away from the hopper ID,- its trailing end in. the direction of travel extending past the nearer edge of the hopper It, as indicated at 8b. Since the open front wall I3 of the hopper I is near the hopper I0, materials fed onto the prongs may be of such depth as to tumble forward over the end 82) of the plate 8 as indicated by the line 9, before transported thereto by the prongs 3. Obviously, if the plate 8a is slid to dispose the end to farther out over the hopper ID, the material will find its normal slope, as indicated by the line 8a, and will hold back additional material in the hopper 7 until that on the prongs is actually transported by the prongs to the end 82) of the plate. Thus by moving the plate 8 todispose the end 81) nearer the hopper it, the amount of material fed is increased and by moving it more remote from the hopper, the amount can be decreased until the predetermined minimum capacity of the feed, depending on the opening in the wall 93, is reached. In extreme cases, the opening in the wall i3 may be reduced by partial blocking in any desired manner.

Beginning at the juncture of the dead plate 8 with the nearer limit of the hopper IE] and extending longitudinally of and in the direction of travel of the prongs are a plurality of longitudinally extending non-magnetic grill bars I4, the bars M being spaced from each other laterally of the path of travel of the prongs 3 so as to form therewith, above the receiving hopper H), a checker grill. The bars M are preferably coexensive longitudinally with the hopper [9 but may extend a short distance beyond the remote edge thereof.

Referring to Fig. 4, each of the chains preferably comprises outer and inner links l6 and i1, spaced apart with suitable roller bearings l8 therebetween. In order to properly guide the chains, non-magnetic tracks i9, one to each chain, are provided, the tracks engaging the roller bearings between the links of the chains respectively. The roller bearings 88 are of smaller diameter than the height of the links so that the links of the chains may engage opposite sides of their respective tracks and act as flanges.

In order to maintain a full depth bed of material on the prongs and to protect the chains, suitable non-magnetic guide plates 20 are provided along opposite sides of the path of travel of the prongs 3, these plates extending a sufficient distance above the upper surface of the prongs to retain the material. The plates 28 are mounted on suitable non-magnetic guards 2! which are arranged in overhanging relation to the linksof the chains so as to prevent material falling onto the chains proper.

Thus as the chains are moved continuously in the direction indicated by the arrows 22, material drops continuously from the hopper $5 onto the prongs 3, is retained therebetween by the non-magnetic dead plate 8 until over the hopper H3, whereupon it drops through the grill formed by the prongs 3' and grill bars 14 into the hopper Hi, the rate of feed of such material being'determined by the speed of the drive of the chain by the sprocket 4.

In order to remove any magnetically responsive material, such as tramp iron and the like from the materials being fed, a plurality of direct side of the path of travel.

current of electro-magnets 23 are provided. The magnets 23 are mounted in upright plates 24 and 25 of high flux conductivity, all poles of like polarity of all the electro-magnets being secured to one plate, for example, the plate 24, and all the poles of the opposite polarity being secured to the other plate 25. The plates 24 and 25 therefore form continuations of the cores of the electro-magnets and terminate in pole heads 26 and 27! respectively, one of which heads extends along one side of the path of travel of the chains and the other of which extends along the opposite In both instances, the pole heads terminate in very closely spaced relation to the chain with which associated.

The pole heads or the resultant magnetic fields are preferably coextensive longitudinally with the hopper 18,01" extend slightly therebeyond so that ,the'prongs are fully magnetized along that portion of their path above the hopper Hi. The prongs 3 of one chain alternate longitudinally of the path of travel with respect to the prongs of the other chain. Further, the prongs carried by each chain preferably terminate in spaced relation to the opposite chain and also to the prongs thereof. Tins latter result may be accomplished by actually terminating the prongs of one chain short of the opposite chain, as. illustrated in Fig. 5, or by providing on. the ends of the prongs suitable elements 28 which are of a material which is non-conductive of magnetic flux and which abut the opposite chain. In either event, the prongs proper, of each chain, that is the --magnetized portions thereof, are spaced from the opposite chain and the prongs thereof. Thus adjacent prongs along the path of travel are of opposite polarity, that is, each positive prong is between two adjacent negative prongs and vice versa.

I Since the chains and their respective prongs are oppositely magnetized they tend to draw toward each other. This may be resisted by the tracks l9, as explained above, or, in the form shown in Fig. 6, by direct abutting relationship of the elements 28 of one chain and the opposite chain. Adjacent prongs 3 may be spaced such a distance apart that the intensity of the field of flux therebetween is substantially equal to that between the ends thereof and the opposite chain. In order that all of the fiux may thus be rendered most effective, the dead plate, the tracks l9, the plates iii and the grill bars 14 may all be of material which will not conduct the flux. The same may be true of any other part of the apparatus sufliciently close to the chains and prongs to by-pass any of the flux and weaken the field between the prongs.

It is readily apparent that as the chains are moved along their path, the material deposited on and between the prongs will be agitated consequent upon movement thereof and any magnetically responsive material will thus be passed between or against the prongs 3. If such material should span two of the prongs it would be tightly gripped thereby inasmuch as it wouldbridge from a north to a south pole of the magnet so formed. If it should touch only one, the magnetic flux between it and adjacent prongs would be intensified due to the resultant shortened air gap and it would be firmly held against the prong I with which in contact. It has been found by actual experience that even when the prongs are stationary, ordinary bolts, pieces of picks, railroad spikes and the like tramp iron can be dropped from a height of a foot or two above the off the end thereof.

prongs and centrally ofthe r'e'sulant "grill openings and any such tramp iron will bedrawn out of its path of fall against the prongs and held firmly thereby. As explained, the magnetic field extends to or past the remote end of the hopper ii) in the direction of travel so that such magnetically responsive material is carried beyond'the hopper. Beyond this point the chain-is not'magnetized and the magnetically responsive material can'readily drop out bet-ween the prongs or pass As'to any residual-magnetism, such is not suificient to hold the material on the prongs, especially along thefdownward portion of the path. For additionally enhancing the demagnetizing 'eifect, the chain' and prongs may be made of soft iron or material which readily demagnetizes when out of-influence of the electro-magnets. 7

Referring next to the driving mechanism for the chain, especially when the apparatus isused in connection with a fuel burning apparatus as described in my copending application, Ser. No.

44,214, filed October 9, 1935, it is desirable'that the rate of feed by the chain and the volume of air admitted to the attrition mill be correlated with respect to each other and also that these be changed in response to room temperatures, boiler pressures and the like. For effecting this relation, the driving mechanism herein shown is provided.

This driving mechanism may comprise a motor 30 having a driving pulley 3! which is connected by a suitable belt or cable drive 32 to the main driving pulley 33 of the change speed mechanism. The pulley 33 is mounted on one end of ashaft 34 which is the constant speed shaft of the driving mechanism and which carries a V-belt driving pulley 35, rotatable therewith, the side members 35a. of which pulley are movable relatively together and apart so that the belt driven thereby may ride nearer or farther from the axis and thus change the relative speed of the belt.

In the form illustrated, a V-belt 36 is provided,

this belt, in. turn, driving the pulley 31 mounted on and rotatable with a shaft 38. Thus the shaft Carried on the shaft 38 and rotatable therewith is a driving pulley which drives a counter shaft 39 through the medium of'the pulley iii secured on one end of the counter shaft 39, anda belt 4!. At the opposite end of the counter shaft 39, a pulley 42 is provided which, in turn, drives a pulley 43 :through the medium of a belt 44, .the pulley 43 being carried on a second counter. shaft 45 and rotatable therewith. At the opposite end of the counter shaft 45 is a pulley which, through the medium of the belt 41, drives a pulley 48 carried on an extension of the shaft 49 mounting the sprocket 4. A suitable hand clutch 56 is provided for connecting the pulley '48 and shaft 49 for rotation together for driving the chain separator and for rendering thewpulley 48 idle respectively. The variable speed shaft 38 is also provided with a pulley which, through the medium of a belt drives a pulley 52 carried by a shaft 53 which drives a fuel oil fuel pump 54. A suitable hand clutch 56 is also provided for locking the pulley 52 and shaft 53 for rotation together for rendering the pulley 52 idle, respectively, so as to drive the pump 54 from the variable speed shaft 38 when desired.

The fixed speed ratios of the pump 54 and the rate of travel of the chain are such that the amount of fuel fed by one at any speed of the shaft 38 will maintain a fire of the same heat intensity as that maintained by the fuel fed by the other at that same speed of the shaft 38. Therefore, in operation of the apparatus, if a change from oil-fuel to coal fuel is required, it is only necessary to disengage the clutch 55 and engage the clutch 50, and vise versa if changing 1 from coal to oil.

Thus a change-over can be made without interruption of the combustion.

As above mentioned, inorder to vary the speed of the variable shaft so that both the pump- 54 and the magnetic feed chain may be operated in response to boiler pressures or the like, a pilot motor 56 is provided. The pilot motor is operated in response to a suitable thermostatic or other control in awell known manner and controls the rate of the speed of the variable speed shaft and consequently the chain and pump by moving the elements 35w'toward and away from each other as the case may be. i

As more fully explained in my copending application, the amount of air admitted to the attrition millshould be controlled in relation to the rate of feed by the chain and for this purpose,

by the same pilot motor. 56 in a fixed geared relation so that uponincrease in the speed of the chain, the shaft 58 will beeperated to admit more air to the mill. 1

It is. apparent from the foregoing description that the magnetic chain feed and separator is highly efficient and utilizes to ,a high degree of efficiency the magnetic fiux produced by the electro magnets, and that. chain feed and driving mechanism isespecially suitable for use in con nection with grinding mills in which the rate of feed and the amount of air admitted must be controlled for accuracy in grind, and that the particular driving mechanism shown effects great accuracy in correlation of the rate of feed an fineness of grind.

, Having thus described my invention,

1 claim:

1. A magnetic chain feed separator comprising the other set ,to a pole of said magnetic means of another polarity, concurrently and continuously, along the said portion of their path of movement, the prongs passing progressively from the influence of the magnetic means along another portion of their path of movement.

2. A magnetic feed separator comprising afrunway, laterally spaced endless carriers continuously movable therealong in substantially fixed position relative to each other, rows of spaced prongs arranged one row on each carrier, the prongs of each carrier extending laterally of the runway and toward the other carrier and terminating in spaced relation to the other row and carrier, and the prongs of'each row being in alternate relation to the prongs of the other row longitudinally of the carriers, and extending past the free outer ends of the other prongs, means for moving said carriers along the runway, said runway being open beneath a portion of the path of travel of said prongs, and magnetic means for magnetizing the prongs of said carriers concurrently during passage of the prongs along said open portion of the runway, one pole of said magnetic means being arranged close to the prongs of one only of said carriers and the opposite pole being arranged close to the prongs of the other one only of said carriers.

3. A magnetic feed separator comprising a runway, laterally spaced parallel tracks on said runway, endless carriers respective to said tracks and continuously movable therealong insubstantially fixed position relative to each other, rows of spaced prongs arranged one row on each carrier, the prongs of each carrier extending laterally of the runway and being spaced longitudinally of the runway and alternated relative to the prongs on the other carrier and extending past the free outer ends of the other prongs, said runway being openbeneath a portion of the path of travel of said prongs, bars extending longitudinally of the runway at the open portion thereof intermediate said tracks, said bars being spaced laterally from the tracks and from each other beneath and in supporting relation to said prongs, whereby a grill of criss-crossing members is formed, magnetic means operable to magnetize the prongs of one carrier at one polarity and the prongs of the other carrier at opposite polarity during passage of the prongs along the open portion of the runway.

4. A magnetic separator comprising a runway, parallel endless chains extending longitudinally thereof at opposite sides of the runway and continuously movable therealong, in substantially fixed position relative to each other, rows of prongs respective to said chains and extending inwardly of the runway from the chain with which associated, the prongs of one chain being in alternate spaced relation longitudinally of the runway to the prongs of the other chain and terminating in spaced relation to the other chain, the free ends of the prongs of each chain extending past the free ends of the prongs of the other, means to magnetize the prongs of one chain at one polarity and the prongs of the other chain at opposite polarity, each of said chains comprising a row of links secured together, and tracks respective to the chains, each track having a surface engageable with side surfaces of said links of the chain with which associated, and operative to hold the chain with which associated in fixed position laterally of the runway when the prongs are magnetized.

5. A magnetic separator comprising a runway, carrier means movable along said runway, said the prongs, magnetic means having a positive magnetic pole atone side of the path of travel of the prongs and a negative magnetic pole at the other side of the path of travel, said poles being substantially coextensive longitudinally with said opening, every other one of said prongs each having one end contiguous to the positive magnetic pole and the opposite end remote from the negative magnetic pole,and the remaining prongs each having one end contiguous to the ,f

negative magnetic pole and the opposite end remote from the positive magnetic pole, and means for moving said carrier means along the runway.

6. A magnetic separator comprising a support, a positive magnetic pole and a negative magnetic pole spaced apart from each other at opposite sides of said support, magnetizable prongs operably associated with said poles respectively, and extending transversely of said support, the prongs associated with the positive pole extending past the adjacent ends of the other prongs and terminating in spaced relation to the negative pole and the prongs associated with the negative pole extending past the adjacent ends of the first mentioned prongs and terminating in spaced relation to positive pole, and said prongs all being spaced apart from each other and providing passages for material therebetween and adjacent prongs being under the influence of opposite ones of said poles and means mounting said prongs for move- H ment relative to said poles and out of the influence thereof;

7. A magnetic chain feed separator comprising a runway, endless carrier means continuously movable along the runway, respective rows of spaced prongs carried by the carrier means, the prongs of each row extending laterally of the runway and terminating in spaced relation to the prongs of the other row and beyond the adjacent ends of the prongs of the other row and defining, with the prongs of the other row, passages for material to be screened, means for moving the carrier means along the runway, said runway being open beneath a portion of the path of travel of said prongs, and magnetic means for magnetizing the prongs of one row at one polarity and the prongs of the other row at opposite polarity during passage of the prongs along the open portion of said runway.

WEBSTER I. SALLEE. 

